1. Field of the Invention
The present invention relates to a multi-tip module mounting a plurality of bare tips, and more particularly relates to a multi-tip module which has improved electrode pads of the module substrate.
This application is based on Patent Application No. Hei 9-173658 filed in Japan, the content of which is incorporated herein by reference.
2. Background Art
In a multiple-tip-module on which a plurality of bare tips are mounted, when the test is carried out for each bare tip by means of a testing device such as a LSI tester, it is necessary to electrically connect the testing device to each electrode terminal of bare tips.
Assume, for example, as shown in FIG. 7, that a multi-tip module is provided with a circuit formed by three bare tips 6a to 6c and eight electrode pads 4 in total. In this case, if it is possible to connect the testing device to each electrode terminal 7 of the bare tips 6a to 6c loaded on the module substrate, the bare tips 7 are capable of being tested as loaded on the module substrate.
However, if the bare tips 6a to 6c are mounted on the module substrate by a flip-tip method and consequently, the electrode terminals are not exposed, the testing device cannot be connected to the electrode terminals of bare tips 6a to 6c. Thus, it becomes necessary to form electrode pads for testing which are connected to each electrode terminal. Particularly, in a multi-tip module shown in FIG. 7. where a part of the circuit is formed in a closed state, it is necessary to form test pads for connecting the test device independently to electrode terminals in the closed-circuit portion. Conventionally, as shown in FIG. 8, a measure was usually taken by providing 16 pads in total, which include 8 pads 4 for connecting at the time of installing the module on the circuit board and 8 pads 4X connecting to the testing device.
However, in a multi-tip module provided with pads for testing, it is necessary to prepare spaces on the module substrate for arranging the testing pads in addition to the installation pads which are originally necessary. Consequently, it becomes difficult to reduce the size of the module, and thereby, realize small-sized multi-tip modules. In contrast, when the size of the module is limited, each pad must be formed in a small restricted area. Especially when a metallic bump structure is adopted and if each pad is formed in a small restricted area, it becomes difficult to form a bump with appropriate dimensions; therefore, it is difficult to preferably install multi-tip modules on a circuit board.
It is, therefore, a object of the present invention to provide a multi-tip module, which is capable of testing bare tips as mounted on the module and which is provided with the installation pads with not restricted and sufficient surface area.